Lea·key /ˈliːki/ a family of British scientists working in the area of paleontology (=the study of ancient animals and plants that have been preserved in rock): Mary Leakey (1913–96), her husband Louis Leakey (1903–72), and their son Richard Leakey (1944–), all of whom discovered many fossils and human bones in Tanzania which have provided important information about how humans first developed